Braking device for vehicles



March 6, 1928.

H. PIEPER BRAKING DEVICE FOR VEHICLES Filed April l5. 1926 wNnH ' causing them to jam, so that it isjn'ot' posradiated Mar. 6, i928.

Uf irren STA HENRI ramena,4 or niuissiins,v BEIJGIUM, issieivoin iro contrae-NIE INTERNATIONALE DEs `manine` aim:oiimvrninns,` soci-ETE anni-mains. or"4 meen: BELGIUM.

BRAKINGIDEVICE FOR- VEBIVCALES. y

Applicationled April 15, 1926, Serial No. 102,1S2, and-in Belgium Octoberiz, 1925.y

It is known that the coel'licient offriction thebrake shoes upon the tires oi wheels decreases as thev speed increases. Consequently, iit is desired to obtain the inaxi- 'it c c main braking, it is necessary' to apply an intense brak'ngforce When the vehicle is travelling at high speed and to decrease. this braking force in proportion 'as the speed 4decreasesuntil' a? relatively blow value is reached Which is sufficient to maintainfthe vehicle at rest upon a given gradient.' i

y lVith the known brake controlling devicesv ly, in order to avoid this jamming, keep Well' below the maximum braking `torce which,

could be exerted upon the WheelsV Without `sibleto make use ofthe maximum efficiency ot the brakingdevice."`

Theobj ect oty the present invention; is 'to re# move these variousdisadvantages by'means4 oi' a device preventingthe jamming of the wheels and allowing, neverthelessythc maximum brakingV to be obtained. c

Fortliis purpose the `braking torce may loe produced onthe one hand bythe coreof a solenoid excited by the current from agencrater actuated by Vthe vehicle or byv the motors oi' the vehicle Working' as generators,

and on the other'handby the core ofa second solenoid subjected to the action otral fluid under pressure; theV releaseot' the brake being produced by cutting off` the current` from the generator or the motor mentioned above and exciting the second solenoid by a current existingu'pon the vehicle.

These two braking systems may be em# ployed either at the same time or-separately, "that is to say one to the exclusion or' the other or the one completing, after a certain period of braking has elapsed, the braking.

force exerted by the other;

The force produced by the fluid under pressure may for example be established in such a Way as to correspond to anormal braking action at low` speeds,- the comple mentary braking action for high speeds being obtained by the action of the core displaced by the solenoid which is excited byV the current from the motors of the vehicle Working as generators.4

The result obtained! froml this varrange-`` res PATENT orties. c

ment is thatthebraki'ng `force reaches the v maximum' at high speeds and decreases inproportion 'as the speed decreases, since the strength of-f the current furnished by the V motors falls; the brakingi'orce, when the vehicle isbrought to rest, correspondingpto the force exerted' by j the fluid under pressure.y 'u l The entry into action of the solenoid ena cited by the current of"V the motors `ofthe vehicle Working as genera-tors,l as Well the admission of the iluid under pressure against the core oi' the second solenoid', may be con@ trolled either by tivo hand levers Whiclrare actuated separately by oremploying a sin-y gle hand lever whichwinaybe the lever of the main controllerwhich` controls the electric motorsolthe vehicle ,Y f c i In the case of, af single handy leverl the valve controlling the,k admission oi fluid underpressure toivards'tlie above mentioned core of the second solenoid is automatic and opens towardsthe vessel containing th'efluid under' pressure'by tlieacti'on oi' `an electro`` magnet interposed in tliecircnit ofthe sole# y' l noid excited bythe-current from the-motors of the vvehicle Working" as generators.

By means Voi' this arrangement thehydrauli'e brake-Will thus enteriiito action di` rectly, While the `electric brake mayv be. gradL uatedfbyvinterposing more on less resist-` anceiny the circuit".

Thebringi ng lback of* `the lever oijthe con,-

troller to tliezero point of its dial will" have the effect von thev one handio breakingthe circuit i of the solenoid suppliedV by the S'm y motors of thevehicleand on the otherihand of'putting into circuit the solenoid acting upon the core' Whiclrihas previously received the pressureot the fluid under pressure.

sureback into its containing vessel.

In the case of trains composed ofa poive'r V dri-ven 'vehicle and several trailerfvehicl'es the brake may he rendered automaticin the eventifoi break occurring in the coupling.` vlilith this ob]ect` in view theinvention` provides for another torni of construction in which the valve controlling the admission of the liuid under pressure upon the core of the second solenoid mentioned above is normally kept closed against the action of the said fluid contained in the vessel under pressure by the core of an electromagnet constantly excited by the current existing upon the power driven vehicle and running throughout the whole length ol the train.

The said 'valve may however be opened during braking operations by a second electromagnet acting upon the valve in an opposite direction to the lirst and interposed 1n the electric braking circuit.

According to a particular advantageous torni of construction the two above mentioned solenoids may advantageously be combined into one single one with aidouble magnetic circuit acting upon a single core resulting from the combination of the two above mentioned cores; this single core thus co-operating in the electric braking and in the pneumatic braking operations.

Other characteristic features of the invention will stand out from the description hereinafter given with reference to the accompanying diagrammatic drawings given by way of example.

In these drawings y y Figure 1 shows diagrammatically a form of a brake actuating mechanism constructed according to the invention.

Figures Q and 3 show diagraimnatically two modified forms of a part of the control mechanism. i

In the form illustrated in Figure 1 use is made of a single solenoid 1 with a double magnetic circuit, comprising a single core 2 moving in a tube 3 of non-magnetic metal and serving as a guide cylinder for the core 2.

The said core is connected at its front part to a rod 1 which acts upon the brake mechanism, shown diagrammatic-ally in the drawings by a pivotally mounted lever 5 carrying the brake shoe 6 which acts upon the wheel 'i' of the vehicle.

The rear part of the c ylinder 3 is placed in communication. through a duct 8, with a vessel 9 containing a fluid under pressure, such as oil; the said duct 9 comprising, at a suitable point, an automatic valve 10 normally held upon its seat by the pressure of the fluid contained in the Vessel 9, which valve is adapted to be opened by the action of an electromagnet 11.

The solenoid 1 comprises two windings 12 and 13, the purpose of which is to actuate the core 2 in the direction of the arrow X and in the opposite direction to the latter respectively. The winding 12 is connected on the one hand to ground, as indicated at 14 and on the other hand to the positive terminal ot a generator actuated by the vehicle 5 which generator may be formed by the motor of the vehicle itself working as a generator. The winding 13 is also connected to any source of current whatever provided upon the vehicle or to the source of current supplying the vehicle in the case ol electric railways or t amways It will be seen that with this arrangement the braking action may be obtained on the one hund by the electromagnetic action cxcried by the winding 12 upon the core 2 and on the other hand by the hydraulic action exerted in the same direction by the i'luid under pressure contained in the vessel fl acting on the rear part ol' the core :2, this intervention ol the said fluid under pressure being controlled by the raising ol' the valve 10. The release of the brakes is then elfected on the one hand by breaking the current in the circuit supplying the winding 12 and on the other hand by exciting the winding 13 in such a way that the force thus produced will be suilicicnt to bring back again the core E2, eventually forcing back into the vessel 9 the fluid under pressure which had been admitted at the rear of the core Naturally the exciting ol the windings 12 and 13 and the putting into circuit of the electromagnet 11 may be ellected by separate controls.

The invention provides however for the control of these various members by the single hand lever l5 of the main controller of the motors of the vehicle.

For this purpose the cleetromagnct 11 is connected in series with the winding 12, and the winding 13 is provided with a contact stud abutting upon the sector ol the controller in such a manner that the actuation ot the level' 15 produces the excitation of the said winding when the lever is brought back into the neighbourhood of the zero mark.

lVith this method of connection the electric brake and the hydraulic brake will act simultaneously. It goes without saying, however, that the intensity ot the electric braking action may be reduced by connccting in the circuit ot the winding 12 a varying number ol rcsistances in such a way that the braking action is obtained.` when the vehicle is travelling at mean speed, practically only by the action of the luid under pressure upon the core 2. the braking torce being subsequently increased it desired by dccreas ing the resistances connected in the circuit supplying the winding 12.

In the form ot construction described above the hydraulic braking and the electric braking operations are ell'ccted simultaneously.

Naturally these two braking operations may be obtained separately; that is to say. one to the exclusion oi' the other or one after the other. One ot the braking operations may for example be employed for low speeds l Uf) llo trol lever, for example the lever ofthe mainv controller of the motor of thevehicle on condition that` these different, control .members of theftwoizirakes are connectedfby circuits judiciously chosen but as the choice of these circuits ,isA within the technical knowledge of all persons skilled inithe art',.itis,notconsidered of useto giveherein adescription` of each of the circuits which wid be necessary for effecting' the different combinations` of the two brake systems mentioned above.

in the case of a train of vehicles composed of a power driven vehicle and several trailer vehicles the brake described above may be rendered automatic in order to obviate breaks 'in the coupling.

For this purpose the method of opening the valve and also its control are modified.

AFigure 2 shows one construction based on this principle in which the valve 10, which is adapted to open under the pressure ofthe fluid contained in the vessel 9, is on the other hand maintained normally closed by the action of an electromagnet 1G supplied by a current extending along the different vehicles composing thetrain.

The valve 10 may also be opened by an electromagnet 11 of higher power than the e-ilectromagnet 16, interposed in the excitation circuit of the electric brake. .lVhen release takes place the fluid under pressure may be forced into the vessel 9 on account of the provision of an automatic valve 17 opening towards the latter.

The modification shown in Figure 3 is based upon the same principle as that shown in Figure 2. It only `differs from the latter in that the core 18 of the electromagnet 16 which normally keeps the valve 10 closed may be actuated in the opposite direction by the electromagnet 11 of greater power than the other.

lVhat I claim is:

1. Brake-operating apparatus for vehicles, embodying an electromagnetic device comprising a. magnetic field traversed by a niagnetic iux created by a solenoid which is excited by current from the vehicle and which shifts in braking direction a core disposed in said field; and a second magnetic field traversed by a magnetic flux created by a second solenoid also excited by current .from the vanne ,and anfang in tangas@- ,leasing direction a core disposed in thesecondvfield, said core being shifted inbraking direction by the action of ,a fluid under.pres- -2. riBrakaoperating apparatus, according to clairnl, in whichthe two cor-es are Joined together.

vBrakeoperatingl apparatusfor vehicles, Y 111 .Winch the brake' lnehanl lslllleetefl with two solenoidcores disposed in a ignment A.with eachother and subjected to tbe action of two magneticfields acting ingop I posite directions, said cores nnpvings in VAnonmagnetic metal tube or cylinder communicating Ywith a reservoir containing a fluid under pressure. f n

4. :Brake-operating apparatus for vehicles, embodying an electromagnetic device coinprising magnetic. field `traversed by a niagnetic flux created by a solencid .which Lis Yexalted by Current litem ,tllenfelilele and which shifts in braking` direction la core disposed in said field; a second magnetic field traversed by a magnetic flux created by a second solenoid also excited by current from the vehicle and shifting in brake-releasing direction a core disposed in the second field, said cor-e being shifted in braking direction by a fluid under pressure coming from a reservoir through a duct; an automatic valve for controlling said duct opening toward said reservoir; and an electromagnet for operating said valve interposed inthe excitation circuit of the r'st solenoid.

5. Brake-operating apparatus for vehicles, embodying an electromagnetic device comprising a` magnetic field traversed by a magnetic flux created by a solenoid which is excited by current from thev vehicle and which shifts in braking direction a core disposed in said field; a second magneticeld traversed by a magnetic flux created by a second solenoid also excited by current from the ,vehicle and shifting in brake-releasing direction a corel disposed in the second field, said core being shifted in braking direction by a fluid under pressure coming from a reservoir through a duct; a Valve for controlling said duct normally closed against the pressure of the fluid in the reservoir by thel action of any electromagnet likewise excited by current from the vehicle; and a second electromagnet of higher power than the rst one for opening said valve and which is interposed in the excitation circuit of the rst solenoid; said duct having a branch with an automatic valve therein which opens towards the reservoir.

,6. Brake-operating apparatus for vehicles,

-embodying an electromagnetic device comprising a magnetic field traversed by a magnetic flux created-'by a solenoid which is excited by current from the vehicle and which shiftsin braking direction a. core disposed in said field; a second magnetic tield traversed by a magnetic flux created by a second solenoid also excited by current from the vehicle and shitting in brake-releasing direction a core disposed in the second field, said core being ,shifted in braking direction by a fluid under pressure coming troni a reservoir through a duct; a valve for controlling said duct: normallyy closed against, the pressure ot the fluid in the reservoir; and a single electrolnagnet. for controllinfr said valve excited by two windings, the first oi which closes the valve and is excited by current from the vehicle. the second Windingr being of higher power than the lirst one and being interposed in the circuit oi the first solenoid; said duct lnivingr a branch with an automatic Valve therein which opens towards the reservoir.

7. Brake-operating apparatus for a vehicle driven by electric motors, embodying an electromagnetic device comprising a :usenetic ield traversed by a magnetic flux created by a solenoid which is excited by current, from the vehicle and which shifts in brakingr direction a core disposed in said Held; a second inaginetic field traversed by a niagnetic tlux created by a second solenoid also excited by current from the vehicle and shitting in lnfnkea'elensing; direction a core disposed in the second fieldt .said corr being shifted in braking direction by n Huid under pressure coming' from :1 reservoir through a duct; and a normally closed valve i'or controlling said duct opened by the action ol an electromagnet interposed in the excitation circuity of tinl first lsolenoid7 the said first sole noid being connected to the motors to he energized thereb)v under the control ot' the lever of the main control when said motoray function as generators.

In testimony7 whereof I aflix my signah ture.

HENRI PIEPER. 

